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Statistics

Types of Data - Normal vs Non-Parametric
Box and Whiskers Graph/ Box plot
Sensitivity and Specificity, PPV, NPV/ Screening/ likelihood ratio
Receiver Operator Characteristics ROC Curve
Meta-Analyses: Forest Plot
Meta-Analyses: Vertical Funnel Plots
Horizontal Funnel Plots: Mortality and Revision Rates
Survival Curves
Reading RCTs/ Error
Designing RCTs: Power, Randomization, Bias, and Blinding
Outcome measures/ Grades of evidence
Interobserver Variability

Types of Data - Normal vs Non-Parametric

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What types of data are there?

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How do you analyze data?

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How do you determine if data is normally distributed?

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How are categorical data summarized and analyzed?

Normal/ Parametric Measurement Data

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What does this image show?

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Why is this considered a normal distribution?

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What is the significance of a bell-shaped curve?

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What are the measures of central tendency? [Descriptive Stats]

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What are the measures for dispersion? [Descriptive Stats]

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What are measures used in inferential statistics?

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What are standard deviations?

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What is the purpose of a statistical test?

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What tests are used for normal (parametric) data?

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How do you test correlation for normal data?

Non-Parametric Measurement Data

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What kind of data distribution is shown in the image? Which side is it skewed to? What do the different colored lines represent?

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What statistical tests are used for non-parametric data?

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How do you test correlation for non-parametric data?

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Can you transform non-parametric data to normal (parametric) data?

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Box and Whiskers Graph/ Box plot

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What is this graph?

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What do the lines represent?

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What is an outlier?

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What does the size of the box indicate?

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Why might the median not be in the middle of the box?

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Sensitivity and Specificity, PPV, NPV/ Screening/ likelihood ratio

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What are sensitivity, specificity, PPV, and NPV?

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Definitions of PPV, NPV, Sensitivity, and Specificity

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Which is more relevant to the patient: Sensitivity or PPV?

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How can you increase sensitivity or specificity?

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What kind of test will you choose to "diagnose as many cases as possible"?

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What kind of test will you choose to "confirm a diagnosis"?

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What is the likelihood ratio?

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What is accuracy?

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What makes a successful screening test? (e.g., for DDH, Scoliosis)

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Example: Is ultrasound screening for DDH a good screening test?

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What biases are screening tests susceptible to?

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Receiver Operator Characteristics ROC Curve

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What is this curve?

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How is the ROC plotted?

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What are the X and Y axes?

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What is the area under the curve?

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Based on this curve, which test is good for screening and which for confirmation?

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How can you improve the test?

Meta-Analyses: Forest Plot

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What is this?

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What is MH?

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What influences the weight?

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What is a confidence interval?

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What is homogeneity/heterogeneity? How is it tested?

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How to address heterogeneity?

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What's the difference between a systematic review and a meta-analysis?

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Meta-Analyses: Vertical Funnel Plots

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What is this?

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What is standard error?

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What does asymmetry show?

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What are funnel plots used for?

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Horizontal Funnel Plots: Mortality and Revision Rates

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What is this? [Mortality Rate]

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What is this? [Revision Rate]

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How are the curves risk-adjusted?

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What are the terms for outliers and those within the normal range?

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What are the criticisms of such analysis?

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Survival Curves

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What is this?

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What are some assumptions in this curve? (3)

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How do you determine if there is a significant difference between the groups?

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What is the downside of this analysis?

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What statistical test do you use to compare these curves?

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Can you derive mean revision time or rate from this curve?

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Reading RCTs/ Error

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What is a confidence interval?

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How does CI differ from P-values? What is a P-value?

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Do you prefer to know the CI or the P-value?

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What is the null hypothesis?

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What is a type 1 (alpha) error? How can it be reduced?

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What is a type 2 (beta) error? How can it be reduced?

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What is a type 3 (gamma) error?

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What are risk ratio (relative risk) and absolute risk reduction?

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What is the Number Needed to Treat (NNT)?

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What is an Odds Ratio?

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What can you interpret from the PROSPECTIVE study result?

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If it is RETROSPECTIVE, what can you interpret from here?

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Designing RCTs: Power, Randomization, Bias, and Blinding

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How do you design a Randomized Controlled Trial?

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How do you conduct a literature review before designing an RCT?

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What are the levels of evidence?

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What characterizes a good Randomized Controlled Trial?

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What are the advantages of randomization?

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How do you implement randomization?

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Types of blinding

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How to calculate sample size and power

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What is bias?

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Types of Bias and How to Address Them

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How to eliminate bias?

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What is a confounder?

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How to address confounders?

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What are key considerations for inclusion and exclusion criteria?

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What are the approaches to analysis of RCTs?

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Which type of analysis is considered the gold standard for RCTs? Why?

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Outcome measures/ Grades of evidence

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What are the types of outcome measures?

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What is a validated outcome measure?

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How do you evaluate outcome measures?

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Examples of Outcome Scores

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What are grades A, B, C recommendations?

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Interobserver Variability

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How to measure interobserver consistency or variability? What tests are used?

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A false balance is an abomination to the Lord, but a just weight is his delight. Proverbs 11:1